Variable-pitch wall forming device for press-fit type underground diaphragm wall and usage method thereof

ABSTRACT

Provided is a variable-pitch wall forming device for a press-fit type underground diaphragm wall, comprising a wall shoe ( 3 ), vibration chambers ( 4 ), a fixed-pitch box ( 1 ) and a variable-pitch box ( 2 ), wherein the variable-pitch box ( 2 ) is installed in the fixed-pitch box ( 1 ), the wall shoe ( 3 ) is installed on the bottom of the variable-pitch box ( 2 ) and the fixed-pitch box ( 1 ), and the vibration chambers ( 4 ) are provided on a side wall of the fixed-pitch box ( 1 ) and a side wall of the variable-pitch box ( 2 ). Also provided is a method of variable-pitch wall forming for a press-fit type underground diaphragm wall.

FIELD OF THE INVENTION

The invention belongs to the technical field of static press-fit (press-in) underground space development. The invention may be used for adjusting the distance in the axial spacing of greater than one, but smaller than two, wall-forming devices when a terminal wall of the continuous underground diaphragm wall is about to be closed (encircled). More specifically, the invention relates to a variable-pitch wall-forming device and methods of use thereof.

BACKGROUND

At present, the normal docking between the wall segments of a press-fit underground continuous wall (hereinafter referred to as a press-fit underground wall) at home and abroad is based on hingedly connecting mechanical connectors one by one in the axial order. However, when the construction is about to complete by encircling the wall, the spacing between the two wall-forming devices, the first and the last, will not leave exactly a standard connection distance for a wall-forming device. From the perspective of accuracy control, it is unrealistic to expect no errors in hundreds or thousands of connections in underground wall construction. Furthermore, the building boundary line will not be premised on the fixed sizes of the wall-forming devices.

The existing techniques for the last-step encirclement of press-in (press-fit) underground walls require human intervention to remedy the remaining gaps. In practice, it has been found that the press-in walls that were enclosed with human help not only have poor water sealing effects, but the joints are also very weak. Such walls have difficulty in performing waterproofing, soil retention, and weight bearing duties. Therefore, overcoming the problem of variable distances in the axial direction at the final connection for two wall-forming devices, the beginning and end sections, is a key technique to ensure that the press-in underground wall will retain its soil-retention, water-blocking, permeability resistance, and load-bearing functions.

SUMMARY OF INVENTION

An object of the invention is to provide devices and methods that can connect a press-in wall ends that have a variable axial distance greater than a single wall-forming device, but smaller than two wall-forming devices. That is, the invention relates to a wall-forming device for press-in underground continuous wall and methods of use.

To achieve the above object, a device of the invention includes a fixed-pitch box, a variable-pitch box, a wall shoe (or wall boot), and a vibration chamber. The variable-pitch box is installed in the fixed-pitch box. The wall shoe is arranged at the bottoms of the variable-pitch box and fixed-pitch box. The vibration chamber is arranged on the side walls of the fixed-pitch box and the variable-pitch box.

The fixed-pitch box comprises a main body, a point connector, and an outer box body. The main body is an open rectangular box having a side-way “U” shaped cross section, which has a long side length of 400-1200 mm, a short side inner length of 200-1000 mm, and a short side outer length of 300-1100 mm. Along the short side wall of the main body, point connectors are arranged vertically (in a column) at a select spacing, and the point connectors are bolted or welded on the side wall. A point connector comprises two rectangular body having the same shape and size, forming a dovetail-shaped trough (groove) at the center of the short sides of the main body. To minimize friction, the point connectors may be disposed along the vertical direction with a large spacing and the vertical length (thickness) may be short. Dovetail trough (groove) is used to be sleeved (coupled) with a dovetail convex track of an adjacent wall-forming device. Once coupled, the wall-forming device and the variable-pitch wall-forming device can only slide vertically relative to each other and cannot separate or move in the radial direction. Point connectors near the junction of the upper and lower sections can be longer to improve the strength. One side of the joint has a seal groove, to facilitate installation of seals to prevent leakage. On the inner walls of the main body, there are two horizontal troughs with an arc-shaped cross section. The first section of the device that enters the soil first is referred to as a main guide section, with a length of ≤50 meters. The bottom of the main guide section is open and is closed with a wall shoe. The section that connects vertically with the main guide section is an extension section. The upper and lower sections connects via junction, which can be secured with bolts. In addition, the upper and lower section joint region also has structures for vertical bolt connections. The shape and structure of the extended section are the same as the leading section. Depending on the engineering requirements for the strength and waterproofing of the supporting structures, these sections can be made to have different lengths and different thickness to meet a variety of specifications. The outer box body is a rectangular box body with a certain thickness and the same length as the main body, and is provided with a section at intervals (spacing) along the vertical direction of the main body, fixed with sunken head bolts on the outer wall of the long side of the main body, spacing is not directly related, but with the wall pressure cylinder stroke to be consistent. Within the cross section area of the outer box, there are sufficient holes for running cables, ducts and waterways in the vertical direction. The upper and lower outer box with the corresponding edge of the shoulder, for the installation of vibrating plates.

The variable-pitch box includes a drawer box, an assembled outer box body, and a dovetail track.

The shapes of the fixed-pitch box and the variable-pitch box are the same. The outer dimension of the long side and the inner short side of the drawer box and the inner side of the long side and the short side of the main body only fit with tolerances. The drawer boxes correspond to the horizontal arc slots of two long sides of the main body. There are mutually consistent long horizontal arc convex track, the drawer box from the short side of the main body open along the horizontal arc slot into the body cavity, and along the main body can move horizontally to the short side of the short side wall, But the vertical was two long sides of the main body up and down a total of two horizontal curved slot to limit the displacement of the bottom of the drawer height=the bottom of the main body−the height of the slope of the wall boots to prevent the drawer bottom wall and the top of the ramp against the wall. When the tank into the underground tank wall closed at the bottom end of the opening. The drawer box is located in the short side of the main body cavity and is called the short side. The short side outside the main body is called the outer short side. The wings on both sides of the outer short side are formed with winged wings. Short side length+outer box body thickness; along the center of the short side of the drawer vertical center vertical or intermittent with dovetail convex track, dovetail track for docking with adjacent wall dovetail device nesting hinged. When squeezed into the ground wall, the remaining space between the two wall-forming devices will eventually change between more than 1 and less than 2 from the axial distance of the wall forming device. Therefore, the outer box body of the drawer box should not be fixed sized, and should be composed of multiple pieces of assembly, called the assembled outer box. Assembled outer box body through the countersunk head bolt fixed to the outer wall of the two long sides of the drawer, the vertical length of the outer body with the main body, the thickness of the outer body of the main body Thickness+length of the main body long side; when used according to the actual distance between the two walls before and after the device to choose different width assembled outer box body composition greater than 1 less than 2 range of any width, combined with drawer with axial displacement fine tuning characteristics Can be successfully completed into the wall device in crowded into the wall at the end of the surrounding area greater than 1, but smaller than 2, mechanical connections between the wheelbase.

The wall shoe is a triangular prefabricated reinforced concrete component as seen from the front elevation, with the upper end of the wall being a certain slope; the intersection of the slope and the lower plane is provided with a step protruding to the periphery horizontally; and the groove on the step plane is provided with a waterproof pad. When the upper end of the wall boots is set into the body and the lower end cavity of the drawer box is squeezed into the ground, the protruding steps of the wall boots bear the full squeezing force transmitted by the distance box+the lower end face of the distance box, Force against the waterproof pad through the closure of the end of the tank+the end of the tank, mud or impurities can not enter from the step into the distance box+tank compartment; when the distance+Resistance and the distance between the tank and the tank+change the gravity mixture on the top of the wall, so that it can not be accompanied by the rise, was permanently left in the ground, wall boots cross-section size can be selected according to the distance box+Size setting.

The vibration chamber comprises a vibration frame, a vibration plate, a vibrator, a water outlet valve, a cable, an air duct, and a water pipe. In the distance between the long distance box+variable length box two vertical outer box (including assembled outer box, the same below), the preparation of a vibration plate, the upper and lower ends with countersunk head bolts in the corresponding outer box on the shoulder, horizontally to the wings with countersunk head bolts bolted to the body+drawer box border, so that a closed cavity volume called the vibration chamber; the main frame is welded to the outer edge of the main body long vertical. The edges of both sides of the drawer box vibrating room are movable borders, which are respectively fixed on the main body frame and the drawer wings by bolts when in use. The plane size of the drawer box frame is larger than that of the main frame and the vibration plate is arranged horizontally in the plane of the drawer box fine-tuning. Electric vibrator with “Ω” card, air vibrator with flange are mounted with bolts on the inner wall of the vibration plate. Cables, duct and pipe connections are disposed in the vibration chamber. A set of vertical water pipes, cable ducts or air ducts are arranged along the cross-sectional area of the outer box and the outer box of the tipping box. The water pipes are set according to the required quantity of the electric vibrators and the water outlet valves. If the use of air vibrator then change the cable duct for the wind. The lower part of the leading segment of the vibration chamber and the extension of the uppermost vibration chamber are provided with vertical water pipe in series with the horizontal circulation pipe, cooling water into the water inlet manifold by the pump into the upper and lower into the lower horizontal circulation pipe and into the adjacent A vertical water pipe, and then from the first vertical water pipe into the upper horizontal circulation pipe into the second vertical pipe down to the next horizontal circulation pipe, thus entering the third vertical pipe upstream. So the cycle eventually To the water mains discharged to the cooling water tank, after cooling water tank and then into the water by the pump repeats cycle. The inner wall of the vibrating plate is provided with a water outlet valve which is communicated with the corresponding water outlet on the vibrating plate, In the exciting force, amplitude and infiltration superposition, the main squeeze out and pull out easily solved. Cables and pipes are “Ω”-shaped (horseshoe shaped) card/plate were fixed in the vibrating chamber main body+drawer box on the long side of the outer wall. The electric vibrator quantity is set according to the electric vibrator or other requirements. The electric vibrator is a high-temperature component when it works, and requires a large amount of cooling water. The air source vibrator neither needs water cooling nor direct power supply, and is a safer and preferred vibration device. Vibrator function is to produce a certain exciting force and amplitude, to reduce the body of the squeeze-in and pull-out friction as well as the concrete vibration to provide aids.

Uses of a device of the invention include three technical aspects: adjusting variable-pitch principles and applications, prefabrication of wall shoes, and mechanical connection to encircle the wall.

(1) variable pitch adjustment principles and applications: based on the actual distance between two front and rear wall-forming devices, the drawer box 22 is moved to the proper position on the ground to start the assembly. If the actual distance between the two wall-forming devices already pressed-into underground is within the fine adjustment range of the drawer box 22, then one only needs to move the drawer box 22 axially for a corresponding distance and there is no need to added the assembled outer box body 7′. Therefore, the drawer box 22 and the vibration plate 21 have their own fine-tuning characteristics for any pitch. Understanding this feature, one can assemble a variable-pitch wall-forming device with many variable pitch parameters, using a combination of the fixed-size assembled outer box 7′ and the vibrating plate 21+drawer box 22.

(2) Wall shoe 3 prefabrication: the wall shoe 3 is produced based on the final axial dimension at the bottom of the wall-forming device. This information was not available before-hand. However, in actual use, continuous pre-fabrication work is required to be carried out in advance. Based on experience, the axial size of the wall shoe 3 is estimated. When prefabricating step 26, the cross-sectional area should rather be larger than smaller. A larger cross section does not affect the use, and the increase in the area of the press-in end is insignificant. The cross section of the slope 25 should be small. A large cross-section of slope 25 may make it difficult to fit in the main body 5+drawer 22 cavity. A small cross-section of slope 25 can be filled in with hard and dry concrete or other fill material and it would be ready to use.

(3) Mechanical connection closure: When the drawer box 22 of the variable-pitch wall-forming device moves axially, the short side 23 of the drawer box 22 moves along with it. The inner short side 23 plays an important role in resisting the strong bracing stress of the multi-functional wall-clamping device and prevents deformation of the long side 15 of the main body. Because the location of the short side 23 of the drawer box 22 in the inner cavity of the main body 5 is not fixed, based on the cavity size divided by the main body 5 and the short side 23 of the drawer box, two reinforcing steel cages are respectively arranged in the cavities of the main body 5 and the drawer box 22 to enhance the rigidity of underground continuous wall. The variable-pitch wall forming device provides mechanical connection of the press-fit wall during the final closure. It connects the first closed press-fit wall-forming device at one end and the last press-fit wall-forming device at the other end. One needs to control the process sequence: Step 1, along the same axis, the dovetail track 11 of the variable-pitch wall-forming device should align with the dovetail trough 10 on the closed wall-forming device, while the dovetail trough 10 of the variable-pitch wall-forming device should align with the dovetail track 11 of the adjacent last wall-forming device. Step 2: couple the variable-pitch wall-forming device with the two connects on the two previously press-in underground wall-forming devices, and gradually press into the ground to a predetermined depth, thereby completing the final mechanical connections for encircling the press-fit wall. Step 3: first, pour concrete into the first closed wall-forming device and gradually pull out the device. Step 4: pour concrete into the last wall-forming device and gradually pull out the device. Step 5: pour concrete into the variable-pitch wall-forming device and gradually pull out the device. The press-fit underground wall is eventually completed without gaps.

The present invention solve a technical problem that connects press-fit underground wall having variable axial distance at the last stage of closure, ensuring that the press-fit wall can function to retain soil, block water, resist permeability, and bear weights.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic illustrating the structure of a device of the invention.

FIG. 2 shows a schematic illustrating the structure in the extended state of a device of the invention.

FIG. 3 shows a schematic illustrating a right side view of a device of the invention.

FIG. 4 shows a schematic illustrating a left side view of a device of the invention.

FIG. 5 shows a cross sectional view along A-A line in FIG. 1.

FIG. 6 shows a cross sectional view along B-B line in FIG. 2.

FIG. 7 shows a cross sectional view along C-C line in FIG. 2.

FIG. 8 shows a front side view of a wall shoe in FIG. 1.

FIG. 9 shows a front side view of a wall shoe in FIG. 2.

FIG. 10 shows a junction between the upper and lower sections.

FIG. 11 shows horizontal trough with an arc-shaped cross section on the main body and the corresponding track on the variable-pitch box.

FIG. 12 shows various connection shapes for wall-forming devices of the invention.

In the Figures, 1 fixed-pitch box; 2 variable-pitch box; 3 wall shoe; 4 vibration chamber; 5 main body; 6 point connector; 7,7′ outer box body; 8 short side; 9 bolts; 9′ flat head (sunken) bolts; 10 dovetail trough (groove); 11 dovetail (protruded) track; 12 junction; 13 seal trough; sealing ring; 15,15′ long side; 16 horizontal trough with arc-shaped cross section; 17 horizontal protruded track with an arc-shaped cross section; 18 main guide section; 18′ extension section; 19 hole; 20 shoulder; 21 vibration room (cavity); 22 drawer box; 23 inner short side; 24 outer short side; 24′ wing; 25 slope; 26 steps; 27 trough (groove); 28 main body frame; 28′ drawer box frame; 29 vibrator; 30 water outlet valve; 31 electrical cable; 32 airduct; 33 water pipe; 34 water inlet main pipe; 34′ water outlet main pipe; 35 horizontal circulation pipe; 36 water outlet opening; 37 water outlet path; 28 spring; 39 “Ω” card/plate (horseshoe-shaped plate); 10-1 “t” shaped trough; 10-2 round trough; 10-3 diamond trough; 10-4 sloped side trough; 10-5 oval (elliptical) trough; 11-1 “T” shaped track; 11-2 round track; 11-3 diamond track; 11-4 sloped side track; 11-5 oval track.

DETAILED DESCRIPTION

Embodiments of the invention will be further described with aid of the following examples and included drawings.

To achieve the above-described objective, a device of the invention comprises a fixed-pitch box 1, a variable-pitch box 2, a wall shoe 3, and a vibrator chamber 4. The variable-pitch box 2 is arranged inside the fixed-pitch box 1. The wall shoe 3 is fixed at the bottom of the variable-pitch box 2 and the fixed-pitch box 1. The vibration chamber 4 is disposed on the side walls of the fixed-pitch box 1 and the variable-pitch box 2.

As shown in FIG. 1, FIG. 5, and FIG. 6, the fixed-pitch box 1 includes a main body 5, a point connector 6, and an outer box body 7. The main body 5 is an open rectangular box body with a sideway “U” shaped cross section, having a long side length of 400-1200 mm, a short side 8 with an inner side length of 200-1000 mm and an outer side length of 300-1100 mm. A pair of rectangular bodies, referred to as the point connectors 6, are arranged at a select spacing vertically along the center of the short side 8 of the main body to form a dovetail-shaped trough 10. To minimize friction, the point connectors 6 are arranged with a large vertical spacing and the vertical lengths of the point connectors 6 are short and are arranged vertically around the center of the short side 8. The point connectors 6 are fixed on the short side 8 using bolts 9 or welding. The dovetail-shaped (cross section) trough 10 is used to connect with the dovetail-shaped (cross section) protrusion track 11 on the neighboring wall-forming device. After snapping together, the wall-forming device and the variable distance wall-forming device can only move vertically by gliding actions between the dovetail-shaped trough 10 and the dovetail-shaped track 11, and they cannot separate from each other or move in the radial direction. Point connects 6 at junctions (joints) 12 of the upper and lower sections may have longer lengths to improve connection strength. There is a close trough on one side of the junction 12 to facilitate the installation of a sealing ring 14 to prevent leakage. On each of the inner walls of the two long sides of the main body 5, there are provided with an upper and lower arc-shaped troughs 16 with a proper spacing between them. The end of the variable distance wall-forming device that enters the ground is referred to as the main guide section 18, which has a length of ≤50 meters. The main guide section 18 has a bottom open end that is closed with the wall shoe 3. Any section that is connected with the main guide section 18 in the longitudinal direction is referred to as an extension section 18′. The joining of an upper section and a lower section at junction 12 may be fixed with bolds 9. In addition, at the facing end of the outer box bodies of the upper and lower sections, there are structures for longitudinal connection using bolts 9. The extension section 18′ has the same shape and structure as those of the main guide section 18. However, the length and thickness of the extension section 18′ can vary to meet the engineering requirements for support-structure strength and water proof requirements. The outer box body 7 is a unitary rectangular shaped box body having a certain thickness and has a dimension in the axial direction that is identical to the long side 15 of the main body. The outer box body 7 is disposed on the main body 5 at a selected spacing along the vertical direction and is fixed with bolts 9 on the outside of the long side 15. The selected spacing for the outer box body 7 is not necessarily related to the spacing of the point connectors 6; however, the selected spacing of the outer box body 7 should coordinate with the travel distance of the wall-pressing cylinder. Sufficient numbers of conduits 19 are included within the cross section of the outer box body 7 to accommodate the power supply cable, air duct, and water pipe. At corresponding edges of the upper and lower sections of the outer box body 7 there are step shoulders 20 for accommodating vibration board 21.

The variable-pitch box 2 includes three components: a drawer box (a sliding box) 22, assembled outer box body 7′, and a dovetail-shaped protrusion track 11.

The variable-pitch box 2 and the fixed-pitch box 1 have the same shape. The lengths of the long side 15′ and short side 23 of the drawer (or “sliding box”) 22 correspond to those of the long side 15 and short side 8 of the main body with a slight difference in length such that they can match. The drawer 22 has an upper and a lower horizontal protrusion tracks 17 with an arc-shaped cross section that match the upper and lower horizontal troughs/grooves 16 with the same arc-shaped cross section. The drawer 22 slides into the inner chamber of the main body 5 from the open end along the arc-shaped troughs 16. The drawer 22 slides horizontally all the way along the long side 15 of the main body until it touches the inner wall of the short side 8 of the main body. The drawer 22 cannot move vertically because it is limited by the horizontal troughs 16 on the long sides 15. The bottom height of the drawer box 22=the bottom height of the main body 5−height of wall shoe slant side 25, such that the bottom of the drawer box 22 will not bump against the top of the wall shoe slant side 25. When pressed-in ground, the variable-pitch box 2 relies on wall shoe 3 to seal off the open bottom end. The short side on the drawer box 22 near the inner chamber of the main body 5 is referred to as the inner short side 23, while the other short side near the open end of the main body 5 is referred to as the outer short side 24. The outer short side 24 is configured like wing shape 24′, and the total length of the outer short side 24, including the wing 24′, equals to the length of the short side 8 of the main body+the thickness of the outer box body 7. Along the center of the outer short side 24, there is provided with a dovetail-shaped protrusion track 11, which can be a continuous piece or in segments. The dovetail-shaped protrusion track 11 is used to engage the dovetail-shaped trough 10 on the neighboring wall-forming device. The distance between the two wall-forming devices at the time of encircling the press-in underground wall is always larger than the axial distance of 1, but less than 2, wall-forming devices. Therefore, the outer box body of the drawer box 22 should not be made in a fixed size, but should be made of an assembly of several pieces, which is referred to as an assembled outer box body 7′. The assembled outer box body 7′ is fixed on the outside of the two long sides 15′ of the drawer box using bolts. The vertical length of the assembled outer box body 7′ is the same as that of the outer box of the main body. Thickness of the assembled outer box body 7′=the thickness of the outer box 7 of the main body+the thickness of the long side 15 of the main body. When in use, depending on the axial distance between the two wall-forming devices, one selects an assembled outer box body 7′ with different widths, to achieve any width within the range, larger than 1 and smaller than 2 wall-forming devices. Furthermore, the drawer box 22 can move in the axial direction to provide fine adjustment. Therefore, one can easily finish the encircling of the press-in underground continuous wall using mechanical sockets within an axial distance of larger than 1, but smaller than 2, wall-forming devices.

The dovetail-shaped trough 10 and the dovetail-shaped track 11 can also adopt other shapes: 10-1 “T” shaped trough, 10-2 round shaped trough, 10-3 diamond shaped trough, 10-4 slant-side shaped trough, 10-5 oval shaped trough, 11-1 “T” shaped protrusion track, 11-2 round protrusion track, 11-3 diamond shaped protrusion track, 11-4 slant-side protrusion track, and 11-5 oval protrusion track. The shapes refer to the cross sections.

The front side perspective view of the wall shoe 3 looks like a precast concrete-steel component, with a slope 25 at the top. The step 26 encircle four sides of where the slope 25 meets the lower horizontal surface. On the step 26, there is a trough 27 for placing a sealing pad. When the top slope 25 is inserted into the lower ends of the main body 5 and the drawer box 22 and pressed into the ground, the step 26 bears the full pressing forces transmitted by the bottoms of the fixed pitch box 1 and the variable-pitch box 2. At the same time, the wall shoe 3 is pushed by the reaction force from the ground, leading to dealing with the sealing pad of the bottoms of the fixed-pitch box 1 and the variable-pitch box 2. Therefore, slurry or contaminants cannot get by the step 26 into the inner chambers of the fixed-pitch box 1 and the variable-pitch box 2. When lifting the fixed-pitch box 1 and the variable-pitch box 2, the wall shoe 3 will be permanently left in the ground because the friction force with the ground, as well as the weight of the mixtures in the fixed-pitch box 1 and the variable-pitch box 2, acting on the wall shoe 3. The size of the wall shoe 3 is based on the dimensions of the selected fixed-pitch box 1 and the variable-pitch box 2.

The vibration chamber includes a main body frame 28, vibration plate 21, vibrator 29, water outlet valve 30, electric cable 31, air duct 32, and water pipe 33. A vibration plate 21 is disposed between the vertical two sections of the outer box bodies of the fixed-pitch box 1 and the variable-pitch box 2 (including assembled type). The upper and lower sections are fixed with bolts 9 at the corresponding outer box shoulder 20. The two horizontal wings are fixed with bolts 9′ on the frame 28 of the main body or on the frame 28′ of the drawer box, thereby forming a closed chamber that is referred to as a vibration chamber 4. The frame 28 of the main body is welded at the two vertical edges of the outside wall of the long side 15 of the main body. The drawer frame 28′ is a moveable frame. It can be fixed on the main body frame 28 and drawer wing 24′ using bolts when in use. The dimensions of the drawer frame 28′ is larger than the main body frame 28. The vibration plate 21 can be disposed such that it can be fine tuned for the horizontal distance. The vibrator, via its “Ω” card, is fixed on the inner wall of the vibration plate 21 using bolts 9, and the air source vibrator is also fixed, via its flange, on the inner wall of the vibration plate 21 using bolts. The connections for electric cables 31, air ducts 32, and water pipe 33 are all in the vibration chamber 4. Within the cross-section area of the outer box body 7 of the fixed-pitch box 1 and variable-pitch box 2, there are water pipe 33, electric cable 31 or air duct 32 running vertically. The number of water pipe 33 is based on the requirements of the electric vibrator 29 and the outlet valve 30. However, the main in-bound water pipe 34 and main out-bound water pipe 34′ only need one each. If the vibrator 29 is an air source vibrator, then the electric cable 31 is replaced with an air duct 32. The water pipes 33 in the vibration chamber 4 at the bottom of the main guide section 18 and the vibration chamber 4 at the top of the extension section 18′ are connected with a horizontal circulation pipe 35. Cooling water is pumped into the main in-bound water pipe and flow down to the lower horizontal circulation pipe 35 and then into the neighboring first water pipe 33, then from the first water pipe 33 into the upper horizontal circulation pipe 35 to enter the second water pipe 33, which then flows into lower horizontal circulation pipe 35 to enter the third water pipe 33. Under the action of the water pump, the water thus circulates and eventually comes out from the main out-bound pipe 34′ to the cooling box. The water is cooled in the cooling box and then recirculated to the in-bound main pipe as described above to repeat the cycles. A water outlet valve 30 is disposed on the inner wall of the vibration plate 21. The water outlet valve 30 includes a spring 38. The water outlet 36 of the water outlet valve 30 is connected with the water outlet path 37 of the vibration plate 21. If the water outlet valve 30 is open, water will spray out to soak the dirt nearby and reduce its hardness. If necessary, one can operate the vibrator 29. Under the actions of vibration and water soaking, pressing-in or pulling-out the main body 5 would be easy. The electric cable 31, sir duct 21, and water pipe 33 are all fixed inside the vibration chamber 21 on the outside walls of the long side 15/15′ of the main body 5 and the drawer box 22. The number of the electric cable 31 depends on the requirements of the vibrator 29 or other devices. In operation, the electric vibrator 29 generates a large amount of heat and needs water cooling. In contrast, air source vibrator 29 would not need cooling water or electrical supply, and this is a safer option for a vibrator. The functions of the vibrator 29 is to generate vibration force and vibration magnitude, which can assist with the pressing-in or pulling-out of the main body 5 by decreasing friction or assist to compact the concrete.

Uses of a device of the invention include three technical aspects: adjusting variable-pitch principles and applications, prefabrication of wall shoes, and mechanical connection to encircle the wall.

(1) variable pitch adjustment principles and applications: based on the actual distance between two front and rear wall-forming devices, the drawer box 22 is moved to the proper position on the ground to start the assembly. If the actual distance between the two wall-forming devices already pressed-into underground is within the fine adjustment range of the drawer box 22, then one only needs to move the drawer box 22 axially for a corresponding distance and there is no need to added the assembled outer box body 7′. Therefore, the drawer box 22 and the vibration plate 21 have their own fine-tuning characteristics for any pitch. Understanding this feature, one can assemble a variable-pitch wall-forming device with many variable pitch parameters, using a combination of the fixed-size assembled outer box 7′ and the vibrating plate 21+drawer box 22.

(2) Wall shoe 3 prefabrication: the wall shoe 3 is produced based on the final axial dimension at the bottom of the wall-forming device. This information was not available before-hand. However, in actual use, continuous pre-fabrication work is required to be carried out in advance. Based on experience, the axial size of the wall shoe 3 is estimated. When prefabricating step 26, the cross-sectional area should rather be larger than smaller. A larger cross section does not affect the use, and the increase in the area of the press-in end is insignificant. The cross section of the slope 25 should be small. A large cross-section of slope 25 may make it difficult to fit in the main body 5+drawer 22 cavity. A small cross-section of slope 25 can be filled in with hard and dry concrete or other fill material and it would be ready to use.

(3) Mechanical connection closure: When the drawer box 22 of the variable-pitch wall-forming device moves axially, the short side 23 of the drawer box 22 moves along with it. The inner short side 23 plays an important role in resisting the strong bracing stress of the multi-functional wall-clamping device and prevents deformation of the long side 15 of the main body. Because the location of the short side 23 of the drawer box 22 in the inner cavity of the main body 5 is not fixed, based on the cavity size divided by the main body 5 and the short side 23 of the drawer box, two reinforcing steel cages are respectively arranged in the cavities of the main body 5 and the drawer box 22 to enhance the rigidity of underground continuous wall. The variable-pitch wall forming device provides mechanical connection of the press-fit wall during the final closure. It connects the first closed press-fit wall-forming device at one end and the last press-fit wall-forming device at the other end. One needs to control the process sequence: Step 1, along the same axis, the dovetail track 11 of the variable-pitch wall-forming device should align with the dovetail trough 10 on the closed wall-forming device, while the dovetail trough 10 of the variable-pitch wall-forming device should align with the dovetail track 11 of the adjacent last wall-forming device. Step 2: couple the variable-pitch wall-forming device with the two connects on the two previously press-in underground wall-forming devices, and gradually press into the ground to a predetermined depth, thereby completing the final mechanical connections for encircling the press-fit wall. Step 3: first, pour concrete into the first closed wall-forming device and gradually pull out the device. Step 4: pour concrete into the last wall-forming device and gradually pull out the device. Step 5: pour concrete into the variable-pitch wall-forming device and gradually pull out the device. The press-fit underground wall is eventually completed without gaps. 

What is claimed is:
 1. A variable-pitch wall-forming device for a press-fit underground continuous wall, comprising: a wall shoe (3), a vibration chamber (4), a fixed-pitch box (1), a variable-pitch box (2), wherein the variable-pitch box (2) is installed in the foxed-pitch box (1), the wall shoe (3) is installed at bottoms of the variable-pitch box (2) and the fixed-pitch box (1), the vibration chamber (4) is installed on side walls of the fixed-pitch box (1) and the variable-pitch box (2).
 2. The variable-pitch wall-forming device according to claim 1, wherein the fixed-pitch box (1) comprises a main body (5), a point connector (6), and an outer box body (7), wherein the main body (5) is an open rectangular box body having a “U” shape horizontal cross section, a long side (15) of the main body (5) is 400-1200 mm long, a short side (8) of the main body (5) has an inner dimension of 200-1000 mm and an outer dimension of 300-1100 mm; the vertical sides of the short side (8) are vertically connected or welded Two pieces of the same shape and size are arranged at the center of the short side (8), and the dovetail shaped rectangular body is called as the point connector (6). The dovetail groove (10) of each point connector The vertical center is vertical; the dovetail slot (10) is used to join the dove-tail convex track (11) of the adjacent wall-forming device; the wall-connecting device and the distance—10) or dovetail convex track (11) can not be separated or moved radially, the main body (5) can be continuously butted together to form a plurality of upper and lower segments, the point connector (6) is butted on the upper and lower segment decks (12) is provided with a sealing groove (13) on one side to facilitate the installation of the sealing ring (14) to prevent leakage, and the inner wall of the two long sides (15) of the main body The appropriate position on each side of the system has horizontal arc slot (18), the length of the leading segment (18) is made less than 50 meters, and the bottom end of the leading segment (18) is closed by the wall boots (3) (18′) vertical docking with the leading segment (18), the upper and lower sections of the upper and lower sections are fixed with butt bolts (9) and the upper and lower sections of the outer box body (7) has the same shape and structure as the main section (18), and the outer box body (7) has a thickness corresponding to the axial dimension of the main body long edge (15) A uniform rectangular box body is arranged along the vertical direction of the main body at a distance from each other and is fixed on the outer wall of the long side of the main body by a countersunk head bolt, Pitch is not directly related to, but with the pressure wall cylinder stroke to be consistent, the outer box body (7) in the cross-section vertical set for the cable duct (31), duct (32), water pipe (33)), The shoulder (20) is arranged on the corresponding edge of the upper and lower sections of the outer box body (7), the vibration plate (21) is mounted on the shoulder (20).
 3. The variable-pitch wall-forming device according to claim 1, wherein the variable-pitch box (2) comprises a drawer box (22), an assembled outer box body (7′), and a dove-tailed convex track (11), wherein the variable-pitch box (2) has the same shape as the drawer box (22) long side (15′) and the inner short side (23) with the length of the main body long side (15) and short side (8) of the inner diameter with the only with tolerance; drawer box (22) (16) of the upper and lower horizontal arc grooves (16) of the inner side wall (15) are provided with mutually parallel long horizontal arc convex rails (17), the drawer box (22) extends from the opening of the main body) Is inserted into the inner cavity of the main body (5) and moves horizontally along the long side of the main body (15) to closely contact the inner wall of the short side (8) of the main body, vertically up and down two horizontal arcuate grooves (16) Limit displacement, bottom of drawer (22) Elevation of base=bottom of base (5) Elevation of height−wall of ramp (25) Height, The drawer box (22) is located at the short side (23) of the short side of the inner cavity of the main body 5, and the short side (24) at the open end of the main body (5) (24′), the total length of the outer short sides (24) of the winged wings (24′) is equal to the length of the inner short sides (23)+the thickness of the assembled outer box body (7′ A dovetail convex track (11) is vertically long or intermittently arranged at the center of the short side (23) outside the box, and the dove-tailed convex track (11) is used for hinging into the dovetail groove (10) adjacent to the wall—The final spacing between the two wall-forming devices during the final encircling is no more than one and only less than the axial distance between two wall-forming devices. Therefore, the outer box of the drawer box (22) can not be made into a fixed size but instead (7′) is fixed to the outer sidewalls of two long sides (15′) of the drawer box by the countersunk head bolts (9′), and the outer box body Vertical length of the main body with the outer box (7), the thickness=the thickness of the main body of the outer shell (7)+the length of the main body long edge (15); when used according to the actual distance between the two walls before and after the device to choose different width assembled Box (7′) composed of more than 1 less than 2 range of any width, combined with the drawer (22) with axial displacement fine-tuning characteristics can be successfully completed wall into the wall device at the end of the encirclement of more than 1 less than 2 The mechanical connection between the wall mount device wheelbase.
 4. The variable-pitch wall-forming device according to claim 1, wherein the wall shoe (3) is a triangular prefabricated reinforced concrete component as seen from the front elevation, with a certain slope (25) at the upper end; a step (26) protruded horizontally around the slope (25) and the lower plane; The step (26) is provided with a groove (27) on the plane for receiving the gasket, and when the upper end slope (25) of the wall shoe (3) is inserted into the cavity of the lower part of the main body (5)+drawer box (26) of the shoe assumes all the pressing force transmitted from the lower end face of the distance box (1)+the distance box (2), and the wall shoe (3) is pressed by the soil body against the seal (1)+Tilt Box (2) bottom surface, mud or impurities can not enter the distance box (1)+Tilt Box (2))+Variable tank (2), due to soil side friction and the distance box (1)+the tank (2) Rise, is permanently left in the ground, wall boots (3) section size can be selected according to the distance box (1)+variable size (2).
 5. The variable-pitch wall-forming device according to claim 1, wherein the vibration chamber (4) includes a main body frame, a vibration plate, a vibrator, a water outlet valve, a cable, an air duct and a water pipe. A vibrating plate (21) is set between every two outer boxes in a vertical direction of the distance box (1)+variable box (2), wherein the outer box comprises an outer box body (7) (7′), the upper and lower ends of the countersunk head bolt (9′) is fixed to the corresponding two sections of the outer box shoulder (20), horizontally to the two wings with countersunk head bolts (9′ (28) and drawer box frame (28′), thus forming a fully enclosed cavity volume called the vibration chamber (4); the main frame (28) welded to the main body long side (15) The drawer box frame (28′) is a movable frame and is fixed to the main frame (28) and the drawer outer short wing (24′) with bolts (9′ The main frame (28) is large, and the vibration plate (21) is arranged to finely adjust the horizontal distance in its plane. The “Ω” card for the electric vibrator and the air source vibrator are mounted on the vibrating plate 21) inner wall, cable (31), duct (32) And the water pipe (33) are all selected to be arranged in the vibration chamber (4) along the longitudinal direction of the longitudinal range of the cross-section of the outer box body (7) of the distance adjustment box (1) (19) for the water pipe (33), cable duct (31) or duct (32); the water pipe (33) is set according to the required number of the electric vibrator (29) and the water outlet valve (34) and the outlet manifold (34′) are each provided with one; if the air source vibrator (29) is used, the cable duct (31) is changed into the duct (32); the lowermost vibration chamber 4), and the water pipe (33) of the uppermost vibration chamber (4) of the extension section (18′) are arranged in series with the horizontal circulation pipe (35). The cooling water is pushed into the water main pipe by the water pump and flows into the lower horizontal circulation (35) into the adjacent first water pipe (33) and then from the first water pipe (33) into the upper horizontal circulation pipe (35) into the second water pipe (33) and down into the horizontal circulation pipe 35) to enter the third water pipe (33) to go up . . . and circulate to the water outlet pipe (34′) finally to the cooling water tank, and after being cooled by the cooling water tank, it is repeated by the water pump into the water inlet pipe (34) Cycle, vibrating plate (21) mounted inside the inner wall The valve (30) and the water outlet hole (36) of the water outlet valve (30) communicate with the corresponding water outlet (37) of the vibration plate (21); water in the water outlet valve (30) The strength is reduced and the vibrator can be activated if necessary (29). When the vibrating force, the amplitude and the wetting superposition effect, the main body (5) is difficult to be squeezed in or out, and the cable duct (31), the air duct The water pipes (33) are respectively fixed on the outer wall of the long side (15/15′) of the main body 5+the drawer box (22) in the vibration chamber (21) by the “Ω” shaped plate.
 6. The variable-pitch wall-forming device according to claim 1, wherein the electric vibrator (29) is a high-temperature component in operation and requires a large amount of cooling water. The air source vibrator (29) does not require water cooling nor direct power supply, and is a relatively safe and preferable vibration device. The vibrator Function is to produce a certain exciting force and amplitude, to reduce the body (5) squeeze in and out of the friction as well as concrete vibration to provide aids.
 7. The variable-pitch wall-forming device according to claim 1, wherein the device comprises the principle and application of variable pitch adjustment, prefabricated wall boots, mechanical connection and closure of three process steps: (1) the principles of variable pitch control and application process steps: According to the actual distance between the two wall-forming devices that have been squeezed into the ground before and after, The drawer box (22) is moved to the right place to start assembly; if the actual distance between the two wall-mounted devices that have been squeezed into the ground is finely adjusted within the drawer box (22), only the drawer box (22), There is no need to add the assembled outer box body (7′). Therefore, the drawer box (22) and the vibration board (21) have fine pitch characteristics of arbitrary pitch variation. By mastering this characteristic, the fixed size outer box body 7′) and the vibrating plate (21)+the drawer box (22) can be combined to form a pitch changing wall device capable of adapting to ten million pitch values. (2) The wall boots (3) are prefabricated in advance. Process steps: 3) is based on the final total length of the bottom wall of the device into the wall to produce the total axial size, in advance and can not accurately grasp the value, but in actual use in order to maintain continuous operation on the need to advance precast; empirically estimated wall boots (3) Axial dimensions, prefabricated when the step (26) section should not be large, The cross-section does not affect the use of large effect, increasing the squeeze into the end of the area can be ignored; and slope (25) section should be small and should not be large, slope (25) Cavity is difficult or impossible, and the section is small enough to be filled with dry hard concrete or other filling material; (3) mechanical connection closure: when the variable pitch wall-mounted drawer box (22) moves axially, the short side 23) is moved along with the short side (23) in the drawer box body (5) cavity position is not fixed, first of all to be solved is based on the main body (5) and drawer short side Cavity size Produce two reinforced cages, respectively, placed in the main body (5) and drawer box (22) of the two cavities to increase the rigidity of the wall included in the calculation, variable pitch wall device as crowded into the wall when the final encirclement of the machinery Connecting device, which is to be connected at one end of the first squeeze into the closed wall device, the other end is squeezed into the ordinary wall device; need to grasp the correct process sequence: the first step, on the same axis, will pitch Wall-mounted device dovetail convex track (11) can only be aimed at closing the wall device dovetail groove (10), and change The dovetail groove (10) of the walling device can only be aligned with the dove-tail convex track (11) of the adjacent final walling device; in the second step, the walling device will be turned into two devices Underground wall into the device connector and gradually squeezed into the ground to a predetermined depth, so the final squeeze into the wall around the mechanical connection process is completed; the first step, first pouring the first closed concrete wall device and gradually pulled out, Step 4, and then pour the other end of the final into the ordinary wall into the concrete device and gradually pulled out, the fifth step, the final pouring into the concrete wall device and gradually pull out into the wall eventually gapless connection. 